Caption: How did Tyrannosaurus have sex? This reconstruction gets the general idea, but doesn't work in the particulars. The details of dinosaur copulation are still unknown. Photo by Mario Modesto, image from Wikimedia Commons.

Daily Mail, HuffPo Dumb Down Dinosex

How did Tyrannosaurus have sex? This reconstruction gets the general idea, but doesn't work in the particulars. The details of dinosaur copulation are still unknown. Photo by Mario Modesto, image from Wikimedia Commons.

Earlier today, the tabloid published a brief article on dinosaur sex that amounted to “Hur hur, dinopeen.” (It’s a close retread of a similarly titled article the Daily Mail published last February.) And the missive is clearly cobbled together from various quotes found around the web, from the ruminations of the late dinosaur sexpert Beverly Halstead to comments from paleontologist Gregory Erickson published at the Huffington Post yesterday. In fact, I have to admit that I’m puzzled by the spurt of attention dinosaur mating rituals have received over the past 24 hours. It’s not as if there’s a bedrock-shaking new study to talk about, or any kind of pertinent hook. I guess, on a slow news day, dinosex sells.

Unsurprisingly, the Tyrannosaurus sex tale has rapidly proliferated across the internet. While I’m generally happy to see dinosaurs bask in the media spotlight, though, the Daily Mail and HuffPo stories piss me off. The stories are simply excuses to show off computer-generated dinoporn and, in the process, they trivialize the actual, amazing science behind our growing understanding of how dinosaurs reproduced. I wrote an article on this very subject for Smithsonian, and followed that up with a four part series (1,2,3,4) earlier this year, but let me hit a few of the highlights.

Thanks to globs of specialized bone inside well-preserved dinosaur fossils, paleontologists can now identify pregnant dinosaurs. No one has found a way to reliably sex all dinosaurs, but, thanks to this peculiar type of tissue (called medullary bone), we can pick out gravid females from among the lot. And that’s not all. By combining this tissue type with studies of how old dinosaurs were when they died, paleontologists Andrew Lee and Sarah Werning figured out that dinosaurs started mating early, long before they reached skeletal maturity. In other words, many dinosaurs were undoubtedly teen moms. This has important implications for how the biggest dinosaurs mated. Even though giants like Apatosaurus could stretch to 80 feet, and even bigger titans such as Argentinosaurus grew to be over 100 feet long, these dinosaurs started having sex at smaller sizes. It’s entirely possible that the reproductive lives of sauropods were limited to a few years after they became sexually mature, before they got so big that sex because difficult or dangerous. There’s no need to speculate that Brachiosaurus and kin relied on Jurassic hot tubs of just the right depth to fool around in.

Even better, the fact that we can now reconstruct dinosaur feather colors means that – with adequate sample sizes – paleontologists can examine whether or not fluffy dinosaurs put on breeding colors, or if there were color differences between males and females. Even if the results come back negative, that will help us better understand dinosaur social lives and behavior. There’s a lot more to the science of dinosaur sex than what position they preferred.

In fact, I think many paleontologists have been lax in their circumlocutions about dinosaur mating. Everyone is agreed that male dinosaurs mounted females, most likely from behind, so that the pair could bring their cloacal openings into contact. There are enough illustrations of the archosaurs going at it dinostyle to fill a book. But look closely at these images, as well as those posted with the Daily Mail and HuffPo stories. The tails of the male dinosaurs aren’t in the right position to inseminate the females. Their cloacal openings, which exited between a backward-pointing bone of the hip and the base of the tail, aren’t very close to the genital opening of the female. The dinosaurs are frustratedly, ineffectually humping.

Figuring out the mechanics of dinosaur sex isn’t so simple as it sounds. We need to take a more rigorous and detailed approach to figure out whether male Triceratops, and its disparate relatives, really did throw their legs over the backs of their female partners. Even then, the same positions wouldn’t have worked for all dinosaurs. Just think of Stegosaurus, with that long row of alternating plates. This dinosaur, and its similarly armored relatives, must have had different tactics to avoid injuring each other in the process of making the next dinosaur generation.

Contrary to the Daily Mail and HuffPo articles, we really don’t have a refined idea of dinosaur sex positions. In fact, the most startling discoveries about dinosaur sex involve other aspects of their biology and behavior. We are gaining a more intimate look at dinosaurs than ever before, so skip the paleo porn and check out the real science.